If you're making the characters simple,
of course the background art has to be made to match that.

Rough characters with detailed backgrounds don't fit together.
The more detailed the background,
the more the characters in front of it seem to be floating above it.

"How do we produce richness as a picture
without relying on the depiction of detail?"
The art director Mr Takeshige and I spent several days scratching our heads.[1]

After a lot of agonizing we came out with: "Animation is pictures, so if we paint them like pictures, that should be all right".

The opportunity came in the preparation stages, when we were referring to an early-modern oil painting from Western Europe. Just like in oil painting or in tempera[2], by showing a light touch with the brush, and bold use of colour, we thought we could create rich vistas on screen without being shackled to photographic realism.

This way of thinking, in the result, is linked to the "neo-classicism" I wrote about the other day.

Translator's Notes

[1]: Literally, 'twisting our necks' (as I suppose, they tried to get their
heads around it).

[2]: The technique of using egg based paints standard in medieval Europe prior
to the invention of oil paints.